1. Field of the Invention
The present invention relates to a method and system for controlling mechanism sections of a printing apparatus.
2. Description of the Related Art
Mechanism sections such as a print head, a paper feed mechanism, and a carriage drive mechanism in a conventional printing apparatus are controlled according to a control program executed by a CPU (Central Processing Unit) built into the printing apparatus. This control program is normally stored in a ROM (Read-Only Memory) in the printing apparatus. When control parameters necessary to control the mechanism sections are changed, even if the number of control parameters to be changed is small, the entire control program must be changed. Therefore, a currently used ROM must be replaced with another one.
The ROM stores a control program including mechanism section control parameters such as excitation time of the print head, a paper motion amount of the printing sheet in automatic paper feeding (i.e., an aligning amount of printing sheet at the start of printing), and acceleration/deceleration data of a carriage motor. These control parameters are predetermined by the characteristics of the mechanism sections, the excitation characteristics of the print head, a position of a paper end switch for determining an auto load amount of the printing sheet in automatic paper feeding, the characteristics of the carriage motor, and printing timings, and the like. For example, when a control parameter of 100 .mu.s as the excitation time of the print head is changed to 200 .mu.s by exchange of the print head, a control program must be entirely changed because the conventional printing apparatus is fixed the control parameters. Therefore, a plurality of ROMs (i.e., a plurality of control programs) must be prepared as maintenance components for the mechanism sections when the control parameters are changed.
It is desireable to control the mechanism sections without replacing the ROM for storing the control parameters even if the states of the mechanism sections in the printing apparatus are changed.